Invertible anode side channel



Feb. 6, 1968 F. H. 'FISCHER ETAL 3,357,855

INVERTIBLE ANODE SIDE CHANNEL 2 Sheets-Sheet l Filed Nov. 2, 1964IVENTORS DELAY FlsCER mmw ATTORNEY Feb. 6, 1968 F, H. FISCHER ETAL3,367,855 i Filed Nov. 2, 1964 2 sheets-sheet a NNNNNNN R5 @ANOS H. FISHER RL F. EART- DELRAY E. FlSCH BYJZMMMMMW ATTORNEYS United StatesPatent O 3,367,855 INVERTEBLE ANDE SIDE CHANNEL Francis H. Fischer andKarl F. Bartels, Portland, and

Delray E. Fischer, Corpus Christi, Tex., assignors to Reynolds MetalsCompany, Richmond, Va., a corporation of Delaware Filed Nov. 2, 1961i,Ser. No. 408,265 4 Claims (Cl. 204-67) This invention relates to animproved electrolytic cell for the production of metallic aluminum. Moreparticularly, this invention is concerned with invertible anode sidechannels for such an electrolytic cell of the Sderberg or self-bakingtype.

Electrolytic cells for the production of metallic aluminum frequentlyemploy self-baking, consumable, carbonaceous anodes encased andsupported on at least two faces by courses of horizontal anode sidechannels which are in turn supported by the cell superstructure. Toprovide for its optimum insertion in the electrolytic bath, the anode islowered as it consumed, the lowermost courses of side channels beingremoved when they approach sufficiently close to the hot electrolyticbath and additional channels being used to form a new top course asrequired. Electric current is supplied to the anode by steel anode pinsextending into the anode through holes in the webs of the side channels.These anode pins, which are driven into the anode while it is in theunbaked or plastic condition, also transmit the weight of the anode tothe side channels` The constant load on the side channels tends todistort and weaken them at the high temperatures present in the cell. Inaddition, the side channels beco'me eroded by the liquid bath or theatmosphere immediately above it. Since both of these phenomena becomemore pronounced toward the surface of the bath, their effects upon anindividual channel are non-uniform. Accordingly, it has been found thatinverting these side channels each time they are installed in a new topcourse, or at other convenient intervals, will prolong their usefullife.

lt also has been found that increasing the depths of the side channelswill result in a corresponding increase in their useful life and aninversely corresponding decrease in the frequency of removal of thelowermost courses of side channels. It also increases the strength andrigidity of the channels.

On the other hand, it is required that the anode pins be as close aspossible to the surface of the bath in order to minimize the voltagedrop in the portion of the anode therebetween. The limiting factor isthe minimum allowable distance (approximately four inches in oneparticular cell, for example) between the lower flange of the lowen mostcourse of side channels and the surface of the electrolytic bath.Allowing the two to come any closer results in unacceptable distortionor erosion of the channel by the bath.

The foregoing problems and requirements are met by providing, inaccordance with the invention, a row of anode pin holes in the web ofthe side channel adjacent the top flange, and another row adjacent thebottom flange. It is presently preferred to insert the anode pinsthrough only the lower row of holes.

For a better understanding of the invention, and of its other details,objects, and advantages, reference is now made to the accompanyingdrawings, which show, for purposes of illustration only, a presentpreferred embodiment of the invention. In the drawings:

FIGURE 1 is a general diagrammatic sectional View of an electrolyticcell showing one of the long sides of an anode and associated apparatus;

FIGURE 2 is a section taken along line II-ll of FIG- URE l; and

FIGURE 3 is a perspective view of a central portion of a side channel.

Referring now more particularly to the drawings, selfbaking anode 1 isformed by periodically placing a quantity of plastic, carbonaceousmixture in bottomless mold 2 supported on the superstructure (not shown)of the cell in the conventional manner. This anode l. is gradually bakedinto a hard condition as it passes downwardly toward hot bath 3 composedof alumina dissolved in cryolite. Layer 4 of molten aluminum lies on topof carbon cathode 5. Side channels n located adjacent opposite faces ofanode 1 are prevented from moving laterally by bent angle irons 7 heldin rigid position by supporting framework (not shown), a clearance ofabout 1Ainch being provided in order that the channels may slip past theangles freely as the channels are lowered with the consumption of theanode.

Each side channel 6 has an upper row tof holes 8A and a lower row ofholes 8B extending through its web portion. Anode pins 9 are driventhrough lower holes 8B into anode 1 in its plastic or green state, thepins serving to support anode 1 when the side channel 6 through whichthey are inserted is on the bottom course. Channel bar 1li connects theadjacent ends of the side channels at the middle of the anode.

The center jack hanger strap 11 supports the channel bar 1b, which inturn supports side channels 6 at the middle of the anode when thosechannels are a part of the bottom course. This strap 11 is supported bysuitable means (not shown) attached to the superstructure of the cell.This superstructure can be conventional in design and usually has jackscrews which serve to raise and lower the center jack hanger strap asdesired during the operation of the cell.

Suitable end channels (not shown) are connected to opposite end fittings(not shown) welded to the outer ends of side channels 6, and theresulting structure may be supported near the corners of the anode byother means (not shown) similar to jack hanger strap l1 and alsoattached to jack screws operating in synchronism with the center jackscrews. Pins 24 connect channel clips 23 and adjacent channel flanges inorder to give the structure greater strength.

Side channels 6 to the right of hanger strap 11 are interchangeable withthose to the left of the strap and side channels d have greater depth(l5 inches rather than l0 inches, in one particular cell, for example),while at the same time anode pins 9 are brought closer to the surface ofbath 3. This system extends the useful life of the side channels 6,decreases the frequency of removal of the lowermost channels, andminimizes the voltage drop in anode l between pins 9 and bath 3.

While present preferred embodiments of the invention and methods ofpracticing the same have been illustrated and described, it will beunderstood that the invention may be otherwise variously embodied andpracticed within the scope of the following claims.

What is claimed is:

1. In an electrolytic cell, an invertible anode side channel comprising:a web portion bounded by first and second flange portions, and first andsecond groups of spaced holes in said web portion for receiving anodepins, said rst and second groups of holes being adjacent said first andsecond flange portions, respectively.

2. In an electrolytic cell for the production of metallic aluminumhaving a self-baking, consumable, carbonaceous anode mounted for partialimmersion in an electrolytic bath, a plurality of horizontal anode sidechannels disposed with their web portions abutting opposite faces ofsaid anode, and electrically conductive anode pins connected to anexternal source of electric current and extending through said webportions and into said anode, the improvement comprising: upper andlower groups of spaced holes in each said web portion adjacent the upperand lower flanges respectively of each said channel, and at least themajor portion of said pins extending through said lower groups of holes,thereby adapting said pins to be positioned relatively close to saidbath to minimize the voltage drop in said anode between said pins andsaid bath while maximizing the distance between said bath and theclosest said channels, yet enabling said channels to be used similarlyin an inverted position.

3. An electrolytic cell for the production of metallic aluminumcomprising in combination: a self-baking, consumable, carbonaceous anodemounted for partial immersion in an electrolytic bath; a plurality ofhorizontal anode side Channels disposed with their web portions abuttingopposite faces of said anode; upper and lower groups of spaced holes ineach said web portion adjacent the upper and lower anges respectively ofeach said channel; and electrically conductive anode pins connected toan external source of electric current and extending through holes insaid lower group and into said anode; thereby adapting said pins to bepositioned relatively close to said bath to minimize the voltage drop insaid anode between said pins and said bath while maximizing the distancebetween said bath and the closest said channels, yet enabling saidchannels to be used similarly in an inverted position.

4. A method of producing metallic aluminum by operating an electrolyticcell having an electrolytic bath, a self-baking, consumable,carbonaceous anode partly immersed in said bath, a plurality ofhorizontal anode side channels disposed one above the other on oppositefaces of said anode with their web portions abutting said faces, upperand lower groups of spaced holes in each said web portion adjacent theupper and lower flanges respectively of each said channel, andelectrically conductive anode pins connected to an external source ofelectric current and extending through holes in said lower group andinto said anode; said method comprising: lowering said anode toward saidbath as said anode is consumed, repeatedly removing from a said face thelowermost of said channels when said lowermost channel is apredetermined distance from said bath, and thereafter re-installing atleast some of the removed said channels in an inverted position as theuppermost of said channels on one said face, thereby maintaining saidpins relatively close to said bath to minimize the voltage drop in saidanode between said pins and said bath while maximizing the distancebetween said bath and the closest said channels.

References Cited UNITED STATES PATENTS 2,739,113 3/1956 Horseld et al.204-243 HOWARD S. WILLIAMS, Primary Examiner.

D. R. VALENTINE, Assistant Examiner.

4. A METHOD OF PRODUCING METALLIC ALUMINUM BY OPERATING AN ELECTROLYTICCELL HAVING AN ELECTROLYTIC BATH, A SELF-BAKING, CONSUMABLE,CARBONACEOUS ANODE PARTLY IMMERSED IN SAID BATH, A PLURALITY OFHORIZONTAL ANODE SIDE CHANNELS DISPOSED ONE ABOVE THE OTHER ON OPPOISTEFACES OF SAID ANODE OF THEIR WEB PORITONS ABUTTING SAID FACES, UPPER ANDLOWER GROUPS OF SPACED HOLES IN EACH SAID WEB PORTION ADJACENT THE UPPERAND LOWER FLANGES RESPECTIVELY OF EACH SAID CHANNEL, AND ELECTRICALLYCONDUCTIVE ANODE PINS CONNECTED TO AN EXTERNAL SOURCE OF ELECTRICCURRENT AND EXTENDING THROUGH HOLES IN SAID LOWER GROUP AND INTO SAIDANODE; SAID METHOD CONPRISING: LOWERING SAID ANODE TOWARD SAID BATH ASSAID ANODE IS CONSUMED, REPEATEDLY REMOVING FROM A SAID FACE THELOWERMOST OF SAID CHANNELS WHEN SAID LOWERMOST CHANNEL IS APREDETERMINED DISTANCE FROM SAID BATH, AND THEREAFTER RE-INSTALLING ATLEAST SOME OF THE REMOVED SAID CHANNELS IN AN INVERTED POSITION AS THEUPPERMOST OF SAID CHANNELS ON ONE SAID FACE, THEREBY MAINTAINING SAIDPINS RELATIVELY CLOSE TO SAID BATH TO MINIMIZE THE VOLTAGE DROP IN SAIDANODE BETWEEN SAID PINS AND SAID BATH WHILE MAXIMIZING THE DISTANCEBETWEEN SAID BATH AND THE CLOSEST SAID CHANNELS.